Conventionally, an image forming apparatus is known that, on a recording medium, forms a transparent toner image above (on a surface side of) or below (on a recording medium side of) a toner image (color toner image) that forms an image.
For example, an image forming apparatus disclosed in Japanese Patent Laid-Open Publication No. 2010-152209 (for example, see paragraphs [0040]-[0044]) forms a transparent toner image above a color toner image when a recording medium is a glossy sheet, and forms transparent toner images above and below a color toner image when a recording medium is a regular sheet.
In this image forming apparatus, when a transparent toner image is formed above a color toner image, a one-pass print is performed in which a transfer medium is carried only once along an image forming unit. On the other hand, when transparent toner images are formed above and below a color toner image, a two-pass print is performed in which a transfer medium is carried twice along the image forming unit.
However, in the above-described configuration, between the case where the one-pass print is performed and the case where the two-pass print is performed, a difference in an amount of the transparent toner that is transferred to the transfer medium occurs, and as a results, a difference in an amount of the transparent toner that is finally transferred to the recording medium also occurs, and thus there is a possibility that image quality is affected.
In view of the above problem, a purpose of the present invention is to provide an image forming apparatus that allows an amount of a toner (such as a white toner or a transparent toner) that is transferred to a recording medium to be nearly constant and image quality to be improved.